1. Field of the Invention
The present invention relates to wireless communications, and more particularly to establishment of peer-to-peer wireless communications.
2. Description of Related Art
In a typical peer-to-peer wireless communication session, all of the participating users tune their communication devices to a common frequency for the session. Each user can then send and receive signals over that common frequency so as to communicate with the other user(s).
In many cases, peer-to-peer wireless communications operate within a public-use frequency spectrum, which is a set of frequencies freely available for use by members of the public. (While governmental regulations might restrict the manner of use of public use frequencies, regulations usually do not restrict who can use the frequencies.) Contrasted with public-use frequencies, are licensed frequencies, such as those typically employed by wireless telecommunication carriers (e.g., in the 800 to 900 MHz and 1800 to 1900 MHz ranges), which are not freely available for use by members of the public. As a result, public use frequencies may also be referred to as “unlicensed” frequencies.
An example of a frequency range in the public use spectrum is the 462.5625 to 467.7125 MHz band allocated for “Family Radio Service” (FRS). Advanced FRS units, such as Talkabout® handheld radios manufactured by Motorola, Inc., for instance, allow users to select from 14 channels, each defined respectively within the FRS band. Users may also set their devices to use a particular squelch code, or CTCSS code, which effectively allows communication in the selected channel with other devices that are set to use the same CTCSS code. Thus, for instance, a group of users might agree in advance to tune their FRS devices to channel 9 and CTCSS code 20, and the users may then communicate with each other.
Commonly, the users will agree in advance what frequency to use. (In this regard, as used herein, the term “frequency” could mean a single frequency, a frequency range, and/or, more generally, any communication channel.) For instance, the users might call each other by telephone or meet in person to select a frequency to use, and each user will then tune his or her respective device to the selected frequency.
Unfortunately, however, it is often difficult to reliably select a frequency that will support communications in the public use spectrum. Many times, public use frequencies are busy or noisy. Thus, if a group of users decides to communicate on a given frequency and the users then disperse throughout a given area, it is possible that some or all of the users might encounter interference on the agreed frequency. Further, in many cases, a group of users might not be able to get together in advance to agree on a frequency to use.